Add note to readme about how to use GMail or other services to send emails.
Add note to readme about how to use GMail or other services to send emails.

Closes #97.

refinery/refinerycms-inquiries,refinery/refinerycms-inquiries,chrise86/refinerycms-inquiries,chrise86/refinerycms-inquiries,bricesanchez/refinerycms-inquiries